Loren Eiseley's work straddles the boundaries between scientific inquiry and poetic exploration, echoing the legacy of eighteenth-century English natural-history essayists like Gilbert White and W. H. Hudson, as well as American nineteenth-century essayists such as Ralph Waldo Emerson and Henry David Thoreau. These predecessors chronicled their interactions with nature while maintaining a deep aesthetic awareness, a practice that sharply contrasts with the contemporary scientific essay's tendency to suppress the writer’s voice. Eiseley, however, artfully combines these traditions. While his essays delve more deeply into scientific knowledge than Thoreau’s, they often reveal an inner tension between his literary and scientific inclinations. Eiseley reflects this conflict in his work, seeking to blend scientific understanding with poetic insight because he believes that science, without the warmth of human experience, does not suffice to render life meaningful.

Eiseley recognizes the pivotal role that natural-history essayists play in spreading knowledge. He acknowledges the significant impact that eighteenth-century parson-naturalists had on evolutionary studies. These figures, though not scientists by today’s standards, offered a comprehensive, humanistic perspective vital for the birth of evolutionary theory. In contrast to the narrow focus of modern scientific observation and classification, they provided a broad view of life and the world. In our increasingly specialized era, Eiseley champions the popular essay as a vital tool for communication, not just to convey particular scientific facts but also to foster an interdisciplinary cultural awareness of science.

As he interprets scientific concepts, Eiseley warns the informed general audience of the perils of institutionalized science. He critiques its relentless pursuit of knowledge, which often comes at the expense of the environment and other forms of understanding, and its propensity to remain insular within its various specialties, promoting a culture of hero worship. Through his position as a scientist, Eiseley offers a reflective and critical lens on the scientific establishment. He also ponders the nature of time and the creativity inherent in evolution. Eiseley studied Charles Darwin extensively and viewed him as "a master artist" who engaged deeply with life with genuine empathy. This empathetic engagement with all forms of life encapsulates the mission of the literary naturalist and the poet, embodying the core of Eiseley’s humanistic vision.